In-vivo sensing devices, such as thermometers, pH meters, optical scanners, image sensors and so on, can be used for unobtrusively monitoring bodily systems. Some in-vivo sensors move through body lumens and can be remotely controlled. However, it is sometimes desirable to immobilize a sensing device in-vivo for continuous imaging of an in-vivo site, for example, for post surgery monitoring.
In the time immediately after surgery patients frequently experience organ functional problems. For example, during surgery in the gastrointestinal tract (GI) the blood pressure at the vicinity of the surgical site is reduced and peristalsis is arrested. After surgery the blood pressure increases and peristalsis is resumed sometimes causing bleeding from the surgical site into the intestinal lumen.
Also, for example, in treating coronary artery disease, it is sometimes necessary to bypass coronary arteries with a vascular graft, which is surgically attached to the heart, to circumvent a blocked coronary artery. After surgery, cardiac functional problems may occur due to build-up of stenotic lesions or other obstructions to the flow of blood through the implanted graft.
Postoperative monitoring of the gastrointestinal tract is important to avoid allowing too much time to elapse before blood loss into the intestine is detected.
Similarly, it is important that the condition of a vascular graft be monitored, post-surgery, to detect the further build-up of stenotic lesions or other obstructions to the flow of blood through the implanted graft.
Various catheterization procedures are known for assessing the flow characteristics of a blood vessel or blood vessel graft. However, the introduction of catheters into the vascular system may result in damage to blood vessels.
One prior art system describes an implantable system for monitoring blood flow through surgically implanted grafts. The system, which may include Doppler crystal transducers, utilizes a subcutaneously implanted electrical plug-type connector, accessible through an incision at the implant site, and electrical conductors to connect terminals on that plug to the Doppler crystal transducers.
Ultrasound echo imaging is known for visualization and examination of a patient's heart However, methods of echocardiography do not always result in good quality images after cardiac surgery.
Monitoring or imaging in-vivo processes, not necessarily related to post surgical events, may also be an important diagnostic tool. For example, in endometriosis, in which cells that normally grow inside the uterus instead grow outside the uterus. Endometrial cells line the uterus and are normally shed each month during menstruation. When endometrial cells grow outside the uterus, the cells may implant. These implants occur commonly within the fallopian tubes and on the outside of the tubes and ovaries, the outer surface of the uterus and intestines and anywhere on the surface of the pelvic cavity. They can also be found, less often, on the surface of the liver, in old surgery scars or, very rarely, in the lung or brain. The implants cause internal bleeding, which leads to tissue inflammation and later, scarring and possibly infertility. Endometriosis can be suspected based on symptoms of pelvic pain and findings during physical examinations in the doctor's office but neither the symptoms nor the physical examination can be relied upon to establish the diagnosis of endometriosis. Imaging studies, such as ultrasound, can be helpful in studying the pelvis, but still cannot accurately diagnose endometriosis. Direct visual inspection and tissue biopsy of the implants are necessary for accurate diagnosis. Currently, the only accurate way of diagnosing endometriosis is at the time of surgery (either by open standard laparotomy or laparoscopy).
Monitoring an in-vivo site by way of, for example, imaging over a sustained period of hours or days may be beneficial.